(accumulo) branch 2.1 updated: Fixed NPE in ScanServerMetrics (#4598)

[dlmarion]

This is an automated email from the ASF dual-hosted git repository.

dlmarion pushed a commit to branch 2.1
in repository https://gitbox.apache.org/repos/asf/accumulo.git


The following commit(s) were added to refs/heads/2.1 by this push:
     new 5f571506dd Fixed NPE in ScanServerMetrics (#4598)
5f571506dd is described below

commit 5f571506ddf6d7dfc003c2fd9969dda783118550
Author: Dave Marion <dlmar...@apache.org>
AuthorDate: Fri May 24 07:45:40 2024 -0400

    Fixed NPE in ScanServerMetrics (#4598)
    
    A NPE was being raised in ScanServerMetrics.registerMetrics when
    the SSERV_CACHED_TABLET_METADATA_EXPIRATION value was zero, which
    disables the tablet metadata caching and leaves the variable
    tabletMetadataCache referencing null. A test was failing in
    ScanServerConcurrentTabletScanIT that led to this discovery.
---
 .../main/java/org/apache/accumulo/tserver/ScanServerMetrics.java | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git 
a/server/tserver/src/main/java/org/apache/accumulo/tserver/ScanServerMetrics.java
 
b/server/tserver/src/main/java/org/apache/accumulo/tserver/ScanServerMetrics.java
index 365c26ceee..1ba7de6e33 100644
--- 
a/server/tserver/src/main/java/org/apache/accumulo/tserver/ScanServerMetrics.java
+++ 
b/server/tserver/src/main/java/org/apache/accumulo/tserver/ScanServerMetrics.java
@@ -63,9 +63,12 @@ public class ScanServerMetrics implements MetricsProducer {
             "Counts instances where file reservation attempts for scans 
encountered conflicts")
         .register(registry);
 
-    Preconditions.checkState(tabletMetadataCache.policy().isRecordingStats(),
-        "Attempted to instrument cache that is not recording stats.");
-    CaffeineCacheMetrics.monitor(registry, tabletMetadataCache, 
METRICS_SCAN_TABLET_METADATA_CACHE);
+    if (tabletMetadataCache != null) {
+      Preconditions.checkState(tabletMetadataCache.policy().isRecordingStats(),
+          "Attempted to instrument cache that is not recording stats.");
+      CaffeineCacheMetrics.monitor(registry, tabletMetadataCache,
+          METRICS_SCAN_TABLET_METADATA_CACHE);
+    }
   }
 
   public void recordTotalReservationTime(Duration time) {